The purpose of this nested case-control study is to investigate the synergistic relationship between human papillomaviruses (HPV) and diet, cigarette smoking and race, in the development of cervical intraepithelial neoplasia (CIN) among low-income and rural South Carolinians. South Carolina health department family planning clinic clients will be the cohort within which this study is nested. From March 1991 to March 1992 cervical samples were collected from each woman receiving a Pap smear at one of eleven clinics in the Charleston area (N = 8,000). Incident cases will be women developing CIN (either CIN I, II, or III) over this FIRST Award time period who also had a normal Pap smear between March 1991-1992 (and had a cervical sample collected for HPV typing). Controls will be women with normal cervical cytology in 1991-1992 who did not develop CIN in the subsequent follow-up years. The HPV DNA type of these cases and controls will be determined in the stored sample using polymerase chain reaction techniques. Cases and controls will be interviewed over the telephone to determine their active and passive cigarette smoke exposure, age, education, parity, contraceptive use, sexual and reproductive history, and history of sexually transmitted diseases. Dietary intake will be determined using a self-administered short version of the NCI Health Habits and Diet History questionnaire. The analysis will compare cases with controls regarding (a) HPV infection status, (b) cigarette smoke exposure (active and passive), and (c) dietary nutrient levels. We will investigate the consistency of findings across racial groups (blacks and whites) by CIN level. Interaction between HPV 16/18/33 and dietary nutrient levels, smoking exposures, race and contraceptive use, on CIN risk will also be evaluated.